You can have a stack with nodes that are all configured with the master-capability set to OFF. For example, if a stack was operating with no redundancy (for example, with one master-capable node) and the master node failed, all other nodes in the stack restart as standby nodes and there is no master node.
Another example is the case where you dismantle a stack before using the unconfigure stacking or unconfigure switch all command. In this case, individual Summit switches are configured for stacking, not master-capable, and are isolated from a stack master.
In this situation, the only security information available is the failsafe account. If you know the failsafe user name and password, you can log into any node and reconfigure master-capability or redundancy. However, if you do not know the failsafe account information, there is another way you can change the configuration.
The procedure described here is generally not needed if another node that is master-capable is expected to rejoin the stack. If this procedure is used, it is possible that the new master duplicates the master that is expected to rejoin later.
If a node becomes unbootable, refer to the Troubleshooting section for information.
Node reboot initiated with master-capability turned on.
This node then sets an internal indicator that is preserved across the reboot. While restarting, the node notices and resets this indicator, ignores the node master-capability configuration, and becomes a master node.
Because the configuring anycast RP command saves the configuration file to all nodes, the node that just rebooted as master-capable should have access to the security information that was configured for the stack. If a RADIUS server is needed, the selected node requires a network connection for authentication.
The special login ID described above is available only if all the following conditions are met:
If the above conditions are met, five minutes after starting the node and every five minutes after that, the following message appears on the console:
Warning: the stack has no Master node and all active nodes are operating with master-capability turned off. If you wish to reconfigure, you may log in using the failsafe account. Alternatively, you may use the special login REBOOT AS MASTER-CAPABLE with no password to force a reboot of a node with master-capability temporarily turned on.
Using the special login ID does not alter the master-capability configuration permanently. If you restart a node that has been restarted with the special login ID, that node restarts using its configured master-capability, unless you again use the special login ID to restart.
When a node has been rebooted using the special login ID, it becomes a master. While the node is a master, the special login ID is not recognized, even though the entire stack is still configured as not master-capable. To get the special login ID to be recognized, the node must be rebooted again.
If a node has been intentionally separated from the stack without first being unconfigured, its security configuration might be unusable.
config none boot
The switch boots up in stacking mode operating as a master-capable switch. You can then log in using the default admin account with no password.
Note
The special login ID does not function on stacks that have nodes configured to be master-capable, even when the reboot stack-topology as-standby command is issued.